Caption: Angiokeratoma. Light micrograph of a section through an angiokeratoma. This is a rare vascular lesion of capillaries (orange) in the dermis that causes dark red spots on the skin. It also causes secondary epidermal changes, including hyperkeratosis (red, top), a thickening of the top layer of the skin. Magnification: x150 when printed at 10 centimetres wide. Human tissue.